KVM: arm64: PMU: Don't advertise STALL_SLOT_{FRONTEND,BACKEND}

Don't advertise STALL_SLOT_{FRONT,BACK}END events to the guest,
similar to STALL_SLOT event, as when any of these three events
are implemented, all three of them should be implemented,
according to the Arm ARM.

Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230819043947.4100985-5-reijiw@google.com

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index b9633de..6b066e0 100644 (file)
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -758,10 +758,12 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
        } else {
                val = read_sysreg(pmceid1_el0);
                /*
-                * Don't advertise STALL_SLOT, as PMMIR_EL0 is handled
+                * Don't advertise STALL_SLOT*, as PMMIR_EL0 is handled
                 * as RAZ
                 */
-               val &= ~BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32);
+               val &= ~(BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32) |
+                        BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_FRONTEND - 32) |
+                        BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_BACKEND - 32));
                base = 32;
        }